Relay



Sept. 3, 1929. F. H. PRESCOTT RELAY Filed April 1, 1924 Patented Sept.3, 1929.

UNITED STATES PATENT OFFICE.

WARE.

BY MESNE ASSIGNMENTS, CORPORATION OF DELA- RELAY.

Application filed April 1,

This invention relates to magnetically 0perated circuit closers and moreparticularly to reverse circuit relays for battery charging apparatus.

It is among the objects of the invention to obtain the maximum pressurebetween the relay contacts for the minimum cost of construction. Theobjects include also such simplification of construction in relays ofthis type as will be conducive to the reduction of cost of manufactureand to ease in making adjustments.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein preferred embodiments of one form of the presentinvention are clearly shown.

In the drawings:

Fig. 1 is a plan view of a relay embodying the invention, the coverthereof being removed;

Fig. 2 is a sectional view substantially on the line 22 of Fig. 1, thecover being shown in section in this view;

Fig. 3 is a view in the direction of the arrow 33 in Fig. 2, a portionof the apparatus being broken away for sake of clearness and the coverbeing shown in cross section;

Fig. 4 is a bottom plan view of the relay the cover being in position;

Fig. 5 is a view in the direction of the arrow 5 in Fig. 2, the coverbeing removed; and

Fig. 6 is a wiring use of the relay in system.

Referring to the drawings the relay mounting bracket includes a flatbase 21 from which are bent two parallel side portions 22 and two endportions 23 which terminate in apertured ears 24 adapted to receivescrews for attaching the relay to a machine frame such as the frame of adynamo 25 indicated diagrammatically in Fig. 6. The edges '26 of thesides 22 and the surfaces of the cars 24 are grooved to conform with thecylindiagram showing the the battery charging drical outer surface of adynamo frame.

The base portion 21 insulatingly supports terminal bars and 31 receivingterminal screws 32 and 33, and a contact bracket 34 connected by rivet35 with terminal bar 30, an L-shaped magnet frame 36 and a magnet core37 which extends through the frame core and the terminal 1924. SerialNo. 703,528.

39 is located between the terminal bars 30 and the base 21, and thewashers 35 are insulated from base 21. A nonconducting strip 40 islocated between the terminal bar 31 and the base 21 and between base 21and a washer 41 retained upon the end of the core 37 by a nut 42engaging the threaded end 43 of core 37. A washer 45 and the parts 38,21, 40 and 31 are secured between the heads of rivets 44, and theswedged ends 46 of these rivets.

Thus it is apparent that the magnet bars 30 and 31 and the contactbracket 34 are insulatingly supported by the base 21.

Between the core head 50 of core 37 and the magnet frame 36 there arelocated stop bracket 51 and nonconducting discs 52 and 53. Between thesediscs are located a series magnet winding 54 and the shunt magnetwinding 55 shown diagrammatically at 56. One end of the magnet winding55 is attached at 56 to the core 37 and the other end is grounded bysoldering at 57 to a lug extending from the base 21 of the bracket 20.Where the relay is installed in an automobile it is mounted upon theframe of a generator which is mounted upon the engine. Thus the winding55 is grounded upon the frame of the vehicle. One end 58 of the winding54 is electrically connected with the terminal bar 31 and the other end59 of winding 54 is electrically connected with the magnet frame 36.

Frame 36 includes a leg 60 extending substantially parallel to the core37. .The leg 60 is tapped to be engaged pass through holes in washers62, 64 and 65 and through slots 66 in aflexible plate or leaf spring 67attached by riveting to the leg 68 of armature 69 said leg 68 beingapproximately parallel to the leg 60 of magnet frame 36.

The magnetic circuit of the relay therefore includes a stationary partincluding core 37 and frame 36 having pole faces which are in differentplanes, namely the top face of core head 50 and the side surface of leg60. The armature 69, or movable member of the magnetic circuit includesparts extending adjacent the pole faces, and the crossysectional area ofthe air gap between legs 68 and 60 is at least as great as thecross-sectional area by screws 61 which I of the air gap adjacent thecore head 50, and

the armature 69 and frame 36, thereby tending to concentrate flux at theair gaps and to prevent magnetic leakage. It will be noted that thearmature 69 and frame 36 are L- shaped with a leg of one overlapping theleg of another, and with the free legs (horizontally disposed in thedrawings) substantially parallel. By virtue of the slots 66 and screws61, the extent of overlap of the hingedly connected legs and hence theair gap adjacent bolt head 50 can be varied.

Armature 69 carries a contact 70 for engaging contact 71 carried by thecontact racket 34. The stop bracket 51 is provided with a bendableportion 7 2' for engaging the free end of a leaf spring7 3 riveted at74; to the armature 69. Thebracket 51 is provided with a bendable hookportion 75 adapted to extend over into the path of motion into thearmature 69. I As shown in Fig. 2 the hook 75 servesas astop to limitthe retraction of armature 69 from the core 37. By bending the hook 7 5relative to the core 37 the maximum gap between the contact points canbe varied.

y bending the spring stop 72 into various positions relative to the core37 the tension applied by spring 73 can be varied.

The terminal 32 is connected-with a battery 80 which is grounded uponthe vehicle frame and terminal 33 is connected with the dynamo 25 whichis grounded also upon the vehicle frame. Below certain generating speedsthe ma netism produced by current flowing throug the winding 54; alonewill be insuflicient to attract the armature 69 and to close thecontacts 70 and 71. Above a certain engine speed the contacts will beclosed and thereafter held closed by reason of current flowing throughthe magnet winding. I The 0 eration of thereverse current is well knownt erefore it is deemed suflicient to state that so long as the generator1s charging the battery the contacts 7 O and 71 will remain closed a andwhen the generator stops the contacts will be opened due-to reversal ofcurrent in the winding 54.

' It is desirable that the contact pressure between the contacts and 71be relatively great in order that a good electrical connection will bemaintained between the generator and battery regardless of variations ingenerating speed between certain limits. It is'desirable that a magnetcircuit of the relay be such as to minimize losses in magnetism. It willbe noted therefore that the tween the stationary and movable parts ofthe magnet circuit are of a comparatively large cross-sectional area.variations in the width of the air gap will not so seriously afiect themagnetism of the relay. In order to accomplish this result certainportions of the magnet frame and armature overair gap be- Thereforeslight A lap one another, the overlapping portions being 60 and 68, soas to provide an air gap of the necessary cross-sectional area. Anotheradvantage resulting from this improvement of the magnetic circuit of therelay is that the relay cover shown at 90-and which fits over themounting bracket 20 may be constructed of magnetic material such assheet steel without substantially affecting the operation of the relay.Since the magnetic circuit concentrates the flux and tends to preventleakmagnetic body near the age the placing of a substantially afiect itsrelay magnet does not operation.

To adjust initially the minimum air gap between the core head 50 and thearmature 69 the screws 61 are loosened, a shim having a thickness equalto the minimum air gap desired is placed between the core and armatureand the armature 69 is moved so that the contacts 70 and 71 are inengagement and the armature is in engagement with the shim. Then thescrews tween the contacts when open will be suflicient to insureinterruption of the electrical circuit between the battery andgenerator. The spring stop 72 is adjusted to vary the spring tension aplied to the armature 69 in-order to vary t e contact closing periodofthe relay relative to the operation of the generator.

While the forms of embodiment of the invention as herein disclosed,constitute preferred forms, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What I claim is as follows 1. A relay comprising, lectromagnet winding,a magnet core extending through the winding, a magnet frame supportingthe core and having a branch extending outside the winding substantiallyparallel to the core, an L-shaped armature having one leg overlappingthe branch of the magnet frame a substantial amount and closely adjacentthereto and having a leg extending adjacent one end of the core, meanshingedly connecting the magnet frame branch with the armature legadjacent thereto, said ding for moving of said hinge means provioverlapping armature leg toward the magarmature moves to- 61 aretightened. When this adjustment is made, there will be in combination,an

extent of overlapping to 1y spaced therefrom and tending adjacent oneend of the core, and a flexible plate for hingedly securing the magnetframe branch and overlapping armature leg and so constructed andarranged that, as the armature moves toward the core, the overlappingarmature leg will move toward the magnet frame branch, and contactscontrolled by the armature.

3. A relay comprising, in combination, a magnetic circuit includingspaced, overlapping stationary and movable L-shaped members; a flexibleblade securing the over-lapping members together so as to provide an airgap therebetween; adjustable means securing the flexible blade to one ofsaid members for varying the extent of overlapping between said members;a winding for energizing said circuit; and a contact actuated by themovable member.

4. A relay comprising, in combination, a magnetic circuit includingstationary and movable L-shaped members placed with a leg of oneoverlapping the leg of the other, and the free legs of said membersbeing substantially parallel, and including a core attached to one freeleg and extending toward the other free leg; a blade spring connectingthe overlapping legs and normally providing an air gap therebetween;means adjustably securing the blade spring on one of said overlappinglegs, and constructed and arranged for varying the extent of overlappingto vary the cross-sectional area of the air gap between said legs and tovary the air gap between the core and one of the members; a winding forenergizing said circuit; and a contact actuated by the movable member.

5. A relay comprising, in combination, a magnetic circuit includingstationary and movable L-shaped members placed with a leg of oneoverlapping the leg of the other, and the free legs of said membersbeing substantially parallel, and including a core attached to one freeleg and extending toward the other free leg; a leaf spring hingeconnecting the overlapping legs and providing an air gap between saidlegs; means for varying the vary the air gap be tween the core and oneof the members and to vary the cross-sectional area of the air gapbetween the overlapping legs; a winding for energizing said circuit; anda contact actuated by the movable member.

6. A relay comprisim in combination, a

magnetic circuit including stationary and having a leg exmovableL-shaped members placed with a leg of one overlapping the leg of theother, the free legs of said members being substantially parallel, andincluding a core attached to one free leg and extending toward the otherfree leg; a leaf spring hinge secured to one member on the side oppositethe air gap and conmeeting the overlapping legs; means for varying thelength of the hinged connection between said members to vary the air gapbetween the core and one of the members as well as to vary thecross-sectional area of the air gap between the legs; a winding forenergizing said circuit; and a contact actuated by the movable member.

7. A relay comprising an electromagnet having a core; an armatureattractable toward the core; a leaf spring fixed at one end to thearmature to retract the armature from the core; a bracket slotted toprovide separately bendable side by side portions one-of which providesan adjustable stop for limiting the retraction of the armature, theother providing an adjustable stop engaged by the free end of the springto vary the tension thereof; and a contact controlled by the movement ofthe armature.

8. A relay comprising, in combination, a magnetic circuit includingstationary and movable L-shaped members placed with the leg of oneoverlapping the leg of the other; a blade spring connection between theoverlapping legs; a core having one end attached to the free leg of thestationary member and its other end terminating adjacent the free leg ofthe movable member; and means for adj usting the blade spring connectionbe tween the members to vary the distance between the end of the coreand the free leg of the movable member.

9. A relay comprising an electromagnet having a core; an armatureattractable toward the core; a leaf spring fixed at one end to thearmature to retract the armature from the core; a bracket havingseparate portions, each one of which is bendable for purposes ofadjustment without affecting the adjustment of the other portion, theone portion providing an adjustable stop for limiting the retraction ofthe armature, the other providing an adjustable stop engaged by the freeend of the spring to vary the tension thereof; and a contact controlledby the movement of the armature.

In testimony whereof I hereto aflix my signature.

FRANK H. PRESCOTT.

